Method of controlling nematodes

ABSTRACT

3-AMINO-5-N-UNDECYL-1,2,4-OXADIAZOLE AND SALTS THEREOF AND METHODS FOR THEIR USE AS NEMATOCIDES AND AQUATIC HERBICIDES.

3,705,247 METHOD OF CONTROLLING NEMATODES Herman Breuer, Regensburg,Germany, assignor to E. R. Squibb & Sons, Inc., New York, N.Y.

No Drawing. Original application July 24, 1968, Ser. No. 747,103, nowPatent No. 3,575,997. Divided and this application June 5, 1970, Ser.No. 57,390

Int. Cl. A01n 9/28 US. Cl. 424-272 2 Claims ABSTRACT OF THE DISCLOSURE3-amino-5-n-undecyl-1,2,4-0xadiazole and salts thereof and methods fortheir use as nematocides and aquatic herbicides.

This application is a division of application Ser. No. 747,103, filedJuly 24, 1968, now US. Pat. No. 3,575,997.

This invention relates to a novel oxadiazole, namely3-amino-5-n-undecyl-1,2,4-oxadiazole, its salts and their use asnematocides and aquatic herbicides.

Nematodes are round worms which infest soil and attack plants throughoutthe world. Plants infected by pathogenic nematodes have a weak, sicklyappearance. The roots of affected plants are stunted. Numerous galls,knots or lesions form on the roots. The plant may appear nutritionallydeficient.

Methods and compositions heretofore known for the control of nematodeshave usually been either inconvenient to use or too expensive forwidespread application. Many nematocides are highly injurious not onlyto man and animals but are phytotoxic to plants and seeds. It isespecially unexpected to discover an effective nematocide which issubstantially non-toxic to plants. The disadvantages of the prior artcompositions and methods are avoided according to this invention bytreating soil intested with nematodes with the compounds of thisinvention.

The compounds of this invention find further utility as aquaticherbicides. To control aquatic weeds, the compounds of this inventionare applied to the water in which the weeds are growing inconcentrations of from about 0.001 to 10 parts per million, preferablyfrom 0.001 to 2 parts per million of water.

Included among the aquatic plant pests which are conveniently controlledin accordance with this invention are: submersed plants such asbladderwort (iUtriculari sp.), bushy pondweed (Najas sp.), coontail(Ceratophyllum sp.), elodea, fanwort (Cabomba sp.), pondweeds(Pontamogenton sp.), water milfoil (Myriophyllum sp.), waterweed(Anacharis Elodea sp.), water star grass (Heteranthera sp.), and wildcelery (Vallisneria sp.), floating weeds such as duckweed (Lemna),floating fern (Ceratopteris sp.), waterfern (Salvinia sp.), waterhyacinth (Eichhornia sp.), water lettuce (Pistia sp.), and water meal(Wolflia), rooted plants with floating leaves such as water lillies(Nuphar sp., Nyphaea sp.) and lotus (Nelumbo sp.), emersed plants suchas alligatorweed (Alternanthera), arrowhead (Sagittaria), bulrush(Scripus sp.), cattails '(Typha sp., lizardtail (Saururus), rush (Juncussp.), parrotfeather (Myriophyllum), water pennywort (Hydrocotyle sp.),pickerel-weed (Pontederia), sawgrass (Cladium), smartweed (Polygonumsp.), spikerrush (Eleocharis sp.), water leaf Hydrolea sp.), waterprimrose (Jussiaea sp.), cut-grass (Zizaniopsis), black willow (Salixsp.), buttonbush (Cephalanthus sp.) and ditchbank grasses such assouthern cutgrass (Leersia), floating-grass (Paspalum), jaragua(Hyparrhenia), knotgrass (Paspalum), maidencane (Pam'cum), common reedsand watergrass (Hydrochloa). The foregoing list is by way of exampleonly and is not intended to limit the scope of the invention.

United States Patent 3,705,247 Patented Dec. 5, 1972 An importantadvantage to the use of the compounds of this invention is selectivity.Although these compounds exhibit very good herbicidal effect uponaquatic weeds, they have little or no effect upon the usual broadleafvarieties of weeds found on land and, in addition, may be employed athigh rates of application for the control of nematodes in farm cropswithout fear of injury to the seeded crop itself.

In use these compounds are applied in any of a variety of formulations.Preferably the compounds are extended with carriers or conditioningagents of the kind used and commonly referred to in the art as adjuvantsor modifiers. Such adjuvants may be inert solids, surface-active agentsand/or organic liquids.

The compounds of this invention are incorporated in such compositions insufficient amount to exert the desired effect. Usually from about 1 topercent by weight of the compounds are included in such formulations.

Solid formulations may be prepared with inert powders. The formulationsthus prepared are used as such, diluted further with inert solids toform dusts, or suspended in a suitable liquid medium for sprayapplication.

The powders usually comprise the active ingredient admixed with minoramounts of conditioning agents. Neutral clays, for example, theabsorptive attapulgite or the relatively nonabsorptive china clays,diatomaceous earth, walnut shell flour, redwood flour, synthetic finesilica, calcium silicate and other inert solid carriers of the kindconventionally employed in powder formulations are used.

The active ingredient is suitably about 1 to 95 percent by weight of thecompositions. The solids preferably are finely divided and have aparticle size below about 50 microns or, better, below about 20 microns.Dust formulations are prepared using talc, pyrophyllite, tobacco dust,volcanic ash or other dense, inert solids as diluents.

Liquid compositions are prepared by mixing the active compound withsuitable liquid diluent media. The active compound is either in solutionor in suspension in the liquid medium. Suitable liquid media includekerosene, Stoddard solvent xylene, alcohols, alkylated naphthalenes,diesel oil, glycols, and ketones, for example, diisobutyl ketone andcyclohexanone. The active ingredient is preferably from about 0.5 to 50percent by weight of these liquid compositions. These compositions areused as such or extended by emulsification with water.

The wettable powders or liquids of this invention suitably include oneor more surface-active agents, for example, wetting, dispersing, oremulsifying agents. Compositions containing these surface-active agentsdisperse or emulsify easily in water to form aqueous sprays. Thecompositions suitably contain up to 10 percent by weight of thesurface-active agents, but some surface-active agents are effective atless than 1 percent.

Surface-active agents are suitably of the anionic, cationic, or nonionictype. Exemplary of such agents are sodium oleate, sulfonated petroleumoils, alkyl aryl sulfonates, sodium lauryl sulfate, polyethylene oxides,lignin sulfo nates, and the like. Additional suitable agents aredescribed by McCutcheon in Soap and Chemical Specialties, volume 31,Nos. 7-10 (1955).

Nematocidal compositions are applied to cultivated land and mixed withtop soil. The rate of application is suflicient to exert the desirednematocidal action. Dosage depends on the components of the formulation,method of application, type and quantity of nematodes, duration, oftreatment, climatic conditions and lesser factors. Application rates offrom 1 to 50 pounds of the active ingredient per acre are usuallysatisfactory for nematode control, but higher rates may also be used.After application, the compositions are preferably worked into theground to a depth of 4 to 6 inches.

In the case of aquatic weeds, periodic treatments may be required foreffective control in flowing water. In the case of rooted aquaticplants, it is often desirable to employ the active ingredient in a heavyvehicle such as a granule (e.g., attapulgite clay granules) which willcarry it to the stream bed, and which will resist movement by thecurrents, thus increasing the length of time that the herbicide remainsin the vicinity of the weed roots.

On the other hand, to control plants characterized by substantialfoliage floating on top of the water (e.g., duckweed, floating fern,water hyacinth, water lettuce, and so forth), this active ingredient ismore advantageously applied with a carrier lighter than water, such aswood shavings, ground corn cobs or organic emulsions, particularlyinverse emulsions. This results in the herbicide being entrapped in thefoliage as it floats downstream and thus provides convenient exposure ofthe foliage to a high concentration of the herbicide.

Also contemplated within the scope of this invention is the use of saltsof 3-amino-S-n-undecy1-l,2,4-oxadiazole. Salts coming within the purviewof this invention include the acid-addition salts, particularly, thenon-toxic acidaddition salts which result from the reaction of the basewith the inorganic or organic acids. Acids useful for pre paring theacid-addition salts, include, inter alia, inorganic acids, such as thehydrohalic acids (e.g., hydrochloric and hydrobromic acid), sulfuricacid, nitric acid and phosphoric acid, and organic acids, such asoxalic, maleic, tartaric, citric, acetic and succinic acid.

The following examples are representative of the invention, although notnecessarily limiting its scope. All temperatures are in degreescentigrade:

EXAMPLE 1 To a solution of 101 grams of triethylamine in two liters ofanhydrous benzene, cooled to there is added slowly, with vigorousstirring, a solution of 109 grams of dodecanoyl chloride in 500 ml. ofbenzene. The reaction mixture is kept at 5-l0 by cooling in an ice-bath.The mixture is stirred for 30 minutes and the cooling bath is removed. Asolution at 21 grams of eyanamide in anhydrous benzene is added slowlywith vigorous stirring, during which time the reaction mixture is keptat 25-35.

The reaction mixture is diluted with petroleum ether and the crudeproduct separates as the lower layer. The crude product is diluted withdioxane, filtered from the triethylamine hydrochloride and the filtratediluted with petroleum ether to yield the desired dodecanoylcyanamide.

56 grams of hydroxylamine hydrochloride are dissolved in 250 ml. ofpyridine and then 112 grams of dodecanoyleyanamide slowly added and thetemperature is maintained at about 40 by outside cooling. The reactionmixture is kept overnight in a refrigerator, diluted with water and madealkaline with sodium hydroxide solution. The crystals which precipitateare filtered under suction in the cold, then washed with water to obtain3-amino-5-n-undecyl-l,2,4-oxadiazole, M.P. 9l93.

EXAMPLE 2 3-amino-S-n-undecyl-1,2,4-oxadiazole was tested against aspecies of Meloidogyne which produces galls or root knots on the rootsof tomato, cucumber, squash, and so forth. In this test steam-sterilizedsoil is infested with 6 grams of finely chopped galled tomato roots pergallon of soil. 3-amino-5-n-undecyl-1,2,4-oxadiazole is then mixed withthe soil at rates of 0.1 to 0.5 gram per gallon, which are theequivalent to field rates of nematocides now in use. The treatedinfested soil is covered and held for one week, after which tomatoplants, cucumber seeds, and squash seeds are transplanted into fourreplicate subsamples. About four weeks later, the roots are washed freeof soil and the effectiveness of the chemical is determined by countingthe number of galls from treated versus untreated soil. In this test thecompound produced 100 percent root knot control at 0.5 gram per gallonwithout causing injury to the tomato or cucumber plants. The conditionof roots, tops and the height of the plants grown in the treated soilwere normal. No phytotoxicity was observed.

EXAMPLE 3 A nematocidal powder is prepared by blending parts of3-amino-5-n-undecyl-1,2,4-oxadiazole with 20 parts of tfine attapulgiteclay, 2 parts of alkylated naphthalene sulfonic sodium salt wettingagent, 0.2 part of low viscosity methyl cellulose dispersant and 2.8parts of disodium phosphate (all parts by weight). The mixture is groundto an average particle size of about 50 microns and blended untilhomogeneous.

About 5 pounds of this formulation are dispersed in gallons of water andapplied at a rate of 50 pounds of active ingredient per acre to landinfested with pathogenic nematodes. The soil is then disced. Cucumbersgrown in the treated soil are normal and free from nematode infection.

EXAMPLE 4 An aqueous suspension is prepared by mixing 3-amino-S-n-undecyl-1,2,4-oxadiazole with the other ingredients listed below andthen wet milling the mixture.

This suspension mixes readily with water to form substantiallynon-flocculating aqueous dispersions, and is applied using conventionalspray equipment at a rate of 40 pounds of active agent per acre.Tomatoes grown in the treated soil are normal and free from nematodeinfection.

EXAMPLE 5 An emulsifiable oil composition is prepared by blending3-amino-5-n-undecyl-1,2,4-oxadiazole wetting agent and oil togetheruntil a completely homogeneous mixture is obtained.

Parts by wt. 3-amino-5-n-undecyl-l,2,4-oxadiazole 33 Polyoxyethylenesorbitan trioleate l1 Stoddard solvent 56 This composition disperses inwater to form an emulsion suitable for application as a spray. One partof this formulation is diluted with 5 parts water (parts by volume) andthe resulting emulsion applied at the rate of 40 gallons per acre.Squash grown in the treated soil are normal and free from nematodeinfection.

EXAMPLE 6 Nematocidal dust is prepared by blending 3-amino- 5 -n undecyl1,2,4-oxadiazole with the diluents listed below and micropulverizing themix to an average particle size of about 30 microns. The resultingmixture is suitably applied with ordinary dusting equipment at a rate of30 pounds of active ingredient per acre.

Parts by wt. 3-amino-5-n-undecyl-1,2,4-oxadiazole l5 Diatomaceous silica2O Pyrophyllite 60 Lauryl alcohol 5 Cucumbers grown in the treated soilare normal and free from nematode infection.

' EXAMPLE 7 Aquatic herbicidal activity was determined in the fol lowingmanner. Both duckweed and an algae mixture was grown in Hillmans mediumwhich contains:

Mg./l. KNO 1515 C3 ('NO3)2'4H2O KH PO 6 8O MgSO 7H O 492 H BO 2.86 ZnSO7H O 0.22 Na- MoO -2H O 0.12 CD804 M11012 '4H2O FeCl GH O 5.40 Tartaricacid 3 .0

The test compound was then added to half of the tubes. Fronds ofduckweed were added to several tubes and mixed algae were added toseveral others, half containing the test compounds and half not. Theinoculated tubes were placed on slanting boards in a 75 F. constanttemperature room which was illuminated fourteen hours per day. After tendays incubation, the treated and control tubes were compared. In thecontrol tubes a ten-fold increase in frond numbers of duckweed wasobserved. A corresponding increase in the growth of mixed algae was alsonoted. In this test at a concentration of ten parts per million, 3 aminoS-n-undecyl-1,2,4-oxadiazole gave 100 percent control of both mixedalgae and duckweed.

EXAMPLE 8 B-amino-S-n-undecyl-l,2,4-oxadiazole was applied to fiveaquatic plants (Pithophora, Najas, Potamogeton, Water Star-Grass andElodea) as a dilute aqueous solution in a concentration of 10 parts permillion by weight. Fourto six-inch cuttings of each aquatic plant wereplaced in a one-gallon glass jar with dechlorinated tap water. The jarswere tightly covered to prevent evaporation and contamination of thewater. The planted jars were illuminated by cool, white, thin-linefluorescent lamps. The intensity of the illumination of the watersurface was from 60- to IOU-foot candles. The plants were illuminatedfor 10 hours each day from 8 am. to 6 pm. They were allowed to remain inthe jars for a conditioning period of three weeks, during which timefertilizer was periodically added to the jars. At the end of this timethe jars were checked to be sure that the plants were vigorouslygrowing. Any jar with discolored or dead plants was discarded fromfurther use. An aqueous solution containing 10 parts per million of thetest compound was then added to the jars and the jars immediatelytightly sealed. The jars were then maintained under the same conditionsfor an additional three Weeks as during the three-week conditioningperiod. At the end of the test period, the effects of the test compoundswere evaluated. Evaluation of herbicidal etfects for the chemical oneach species of plant was by visual observation, with injury to theplant rated on a scale of 1 (no visible injury) to 10 (a dead plant).Ratings from 1 to 3 indicate no, or very slight, herbicidal actvity,from 4 to 6 indicate moderate herbicidal activity, and from 7 to 9indicate definite to severe herbicidal activity. Independent ratingswere made on each species of plant. These ratings were then averaged foreach of three replications and these results again averaged to determinean overall average effect expressed as percent herbicidal eifectiveness.In this test the compound exhibited an average overall effectiveness ofover percent. In no case did any rating fall below 7.

This invention may be variously otherwise embodied within the scope ofthe appended claims.

What is claimed is:

l. A method of controlling nematodes, which comprises applying to soilinfested with nematodes a composition containing from about 1 to percentby weight of 3-amino-5-undecyl-1,2,4-oxadiazole or salts thereof.

2. A method in accordance with claim 1 wherein the composition appliedto soil infested with nematodes contains from about 1 to 95 percent byweight of 3-amino- S-undecyl-1,2,4-oxadiazole.

References Cited UNITED STATES PATENTS 3,498,998 3/1970 Hughes 7192 XJAMES O. THOMAS, JR., Primary Examiner US. Cl. X.R. 71--66, 67

1 g UIsITED STATES PATENT oFFIcE CERTIFICAETE OF CORRECTION Patent No.17 1 47 Da ted December 5, 1972 9 Inventor(s) Herman Breuer It'iscertified that error appears in the above-id entified patent I and thatsaid Letters Patent are hereby corrected as shown below:

" Column 1, line 60, the phrase (Typha sp. should read:

(Typha sp.) r p I Column 1, line 64 the phrase "leaf Hydrolea sp.)should read leaf (Hy'rolea sp.) I

Column 3 line 66, Example 2," 'aft er' "of soil'." de l Le te the phrase3-amiij1o-5n'-undecyll,2,4-oxad1azole in its place insert the following:I

-- 'lk i z-methyi-l ,3-diphenyll,B-propanedione Column 4 line 61 Example6, "Nematocidal dust" should' read A nematocidal dust Signed and sealedthis 1st day of May 1973.-

(S A Attest:

EDWARD M. FLETCHER, JR ROBERT GOTTSCHALK v Attesting Officer 1Commissioner of Patents

